This invention relates to foot prostheses in general, and specifically to a split prosthetic foot which incorporates a plurality of curvilinear foot portions which cooperate with one another to provide the wearer with performance characteristics not available from prior art prostheses.
A number of prosthetic devices have attempted to provide energy-storing and -releasing functions to simulate ambulation on a natural limb. For example, see my U.S. Pat. No. 4,547,913 for my invention relating to a "Composite Prosthetic Foot and Leg", and U.S. Pat. No. 4,822,363 for my invention relating to a "Modular Composite Prosthetic Foot and Leg". Also, my pending applications Ser. Nos. 07/337,374, 07/585,920 and 07/293,824, now U.S. Pat. No. 5,037,444, disclose prosthetic foot devices with similar preferred materials and methods of manufacture, and with corresponding benefits therefrom.
Each of my aforementioned inventions is characterized by lightweight, elongated structures incorporating polymer impregnation of superimposed reinforcing laminae maintained in the desired configuration. Such configurations and constructions provide the desirable characteristics of strength and flexibility in the prosthetic member, and achieve a simulation of the performance of natural feet which had previously not been attainable. Such prostheses may be provided in modular assemblies, whereby the particular performance characteristics of a given prosthesis may be adapted and readily adjusted to meet the needs and activity level of the individual patient.
Other prosthetic foot devices include U.S. Pat. No. 3,335,428 to Gajdos, which attempts to duplicate the skeletal and skin structure of a natural human foot, U.S. Pat. No. 2,075,583 to Lange, which incorporates a rubber form mounted in operative relationship with a rigid metallic core, and U.S. Pat. No. 4,645,509 to Poggi, which teaches a prosthetic foot incorporating a monolithic keel or beam of relatively massive proportions intended to react to the load of an amputee's body during walking, running, jumping, and the like and to release the resultant stored energy to create foot lift and thrust complementing the amputee's natural stride.
Although several of the aforementioned prostheses have provided flexure in a fore-and-aft direction, such prior art devices are relatively stiff and unresponsive with respect to torsional loading which might result from leaning to one side or from ambulation in a direction other than straight ahead. In fact, such prostheses provide a consistent energy response for loading at any given fore-and-aft location on the prosthesis, regardless of whether the loading occurs at one edge of the prosthesis or at the center thereof.